Journal of Ecological Engineering Received: 2020.07.20 Revised: 2020.08.30 Volume 21, Issue 8, November 2020, pages 91–98 Accepted: 2020.09.15 Available online: 2020.10.01 https://doi.org/10.12911/22998993/127092

Analysis of Optimum Garbage Heaps Age on Recovery of Dominated by Organic Solid

Zaulfikar Abbas1,2*, Sudarno Utomo1,3 and Budiyono1,4

1 Doctoral Program Environmental Sciences of , Semarang 50241, 2 Industrial Engineering Department of Teuku Umar University, 23681, Indonesia 3 Environmental Engineering Department of Diponegoro University, Semarang 50275, Indonesia 4 Chemical Engineering Department of Diponegoro University, Semarang 50275, Indonesia * Corresponding author’s e-mail: [email protected]

ABSTRACT Landfills in developing countries, like Indonesia are dominated by organic solid waste, with water content reach- ing 80%. It is impossible to manage them by processes. Naturally, all organic material can decompose and produce methane gas, carbon, water, as well as leave blackish fine soil-like material, called . There- fore, the recovery of the landfills can be done by using methods. However, the benefits, costs, and environmental impacts of landfill mining are highly dependent on landfills age, material characteristics, disposal systems, economic and social development of the community, and climate. The main objective of this study was to analyze the optimum age of garbage heaps to obtain the right time on the recovery of the landfills. Five excava- tion points were prepared at 4–5, 6–7, 8–9, 10–11, and > 12 years. Each excavated material was dried, separated, and grouped according to each component, and then weighed, tabulated, and shown as a percentage of excavated garbage composition. The result shows that landfill mining can be carried out at a garbage heap aged 8–9 years in which compost landfill mining has obtained at 50%. Other discussions concern the existence of organic and non- organic components as well as the usage of plastic bags and nappies indicating the lifestyle changes of the people.

Keywords: organic solid waste, landfill, landfill mining, compost landfill mining

INTRODUCTION have become urban slums and this constitutes a serious problem in Indonesia. The availability of Generally, landfills in developing countries, a strategic urban land is also increasingly difficult such as Indonesia, still use an open dumping sys- to obtain. tem with bad management and poor processing On the other hand, landfills are sources of facilities. The problem has become more compli- groundwater pollution and emissions of methane cated due to the high rate of urbanization, which gas, carbon, and other hazardous substances in directly affects the waste generated. The technical the long term (Mor et al., 2006; Sormunen et al., aspects, quality of human resources and financing 2008). The condition becomes worse due to inad- are some of the main obstacles in implementing equate processes of sorting and transforming ma- sanitary landfills (Scheinberg, 2010; Coordinat- terials which can still be recycled and reused; this ing Ministry for Economic Affairs, 2013). shortens their service life and requires the cre- Many cities in developing countries, like in ation of new landfills. However, the land-based Indonesia are growing very fast, requiring the system is very vulnerable to community protests expansion of their area. The landfills that were and is not easy to handle (Hadi, 2001; Chang and previously far from the city centers and residen- Davila, 2007). tial areas have become part of city centers and Landfill mining is the right way to recover densely populated. Most areas around landfills landfills. It will increase the economic value of

91 Journal of Ecological Engineering Vol. 21(8), 2020 the lands around the landfills. The cost of land- materials (ferrous/non-ferrous) in ash heaps of fill mining is very high; however, the municipal incinerators (Quaghebeur et al., 2013; Jones et government has a more important mission, which al., 2013; Frändegård et al., 2013; Beaven et al., is avoiding burden costs after the closure of the 2014; Frändegård et al., 2015; Danthurebandara landfills, adding strategic urban land and increas- et al., 2015; Massarutto, 2015; Wagner and Ray- ing land values after recovery of the landfill (Zee mond, 2015; Tanigaki et al., 2015; Burlakovs et et al., 2004; Passel et al., 2013). al., 2016). Landfill mining can also extend service life, Since no studies about the right age of the gar- rehabilitate, and recover landfills in which it also bage heaps, and also the characteristics of land- avert the environmental effects from fills in growing cities Indonesia which -are dif pollution or emissions (Krook et al., ferent from other landfill are available, the main 2012; Frändegård et al., 2013; Fisher and Findlay, objective of this study was to obtain an optimum 1995). Therefore, landfill mining can be adopted age of garbage heaps in producing compost land- as a feasible way for the ecological recovery of fill mining that can be used as the right time on ex-landfill (Krook, 2010; Krook and Baas, 2013). the recovery of landfills in developing countries, However, the benefits, costs and environmen- especially in Indonesia, in which the landfills are tal impacts of landfill mining are highly depen- dominated by organic solid waste with high water dent on several factors, such as land age, material content. Other goals were to discuss the time ef- characteristics, depth of landfill waste, level of fect on an increase in the percentage of compost waste decomposition, hazardous material con- landfill mining and provide an overview of the tents, disposal systems, economic/social develop- current condition of people. ment of local community, climate, humidity, and landfill location (Hogland, 2002; Zee et al., 2004; Krook et al., 2012; Rosendal, 2015). METHODOLOGY Therefore, landfill mining in developed coun- tries is different from that in developing countries. This study was carried out in the Gampong In Indonesia, landfills are dominated by organic Jawa Landfill, Banda Aceh, Sumatera – Indone- solid waste, which reaches 70% and categorized sia. It was conducted from September to Decem- as wet solid waste with water content up to 80% ber 2018, starting with field observations to ob- (Fehr, 2006). tain the information on field conditions and the Thus, management of solid waste by the com- location of garbage heaps based on time. bustion process is impossible. However, naturally, The excavation was based on the age group all organic material can decompose and produce of garbage heaps 4–5 years, 6–7 years, 8–9 years, methane gas, carbon, and water. The remaining 10–11 years, and ≥ 12 years. In each age group, organic material forms blackish fine soil-like ma- the excavation was carried out at three different terial which is called compost. depths 3–4 meters, 6–7 meters and ≥ 9 meters, There are many studies of landfill mining, but then the percentage of the excavated garbage of there are no specific studies regarding the age of each age group is an average of the three differ- the garbage heaps in order to obtain the right time ent depths. A long arm excavator was used due to on recovery of landfills, especially in an active temporary transfer and return of garbage over a landfill. The REMO Belgian landfill is one of the large area. many old landfills. A study conducted in the land- The excavated garbage was dried under sun- fill was reported, in which 4 locations for exca- light for 5–7 days, or until the weight stayed con- vated samples were selected at 14, 19, 24 and 29 stant for the last three days. Then it was sorted years (Quaghebeur et al., 2013). A similar study manually by hand to separate rough materials was carried out in Tamangapa landfill in Makas- including wood, plastic, metal, glass, rubbers, sar Indonesia but at 6 years cells (Darwati, 2009). cloths, paper, cardboard, and other materials that The studies on the utilization of compost do not have any economic or caloric values. The landfill mining as bio-cover were also been re- remaining material is called the compost landfill ported (Barlaz et al., 2004; Kurniasari et al., 2014; mining component, and together with rough ma- Silas et al., 2014). The majority of other studies terials it was weighed, tabulated, and determined are reviews of the potentials of landfill mining/ as the composition of the excavated garbage. enhanced landfill mining, including mining metal

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RESULTS AND DISCUSSION it will also be corrected from 55.91% to 62.42%. If all data above is used, there are two pieces of The percentage of compost landfill mining inaccurate data, i.e. the data on excavation point based on the age of garbage heaps at 10–11 years and ≥ 12 years. However, if the data on the excavation point at 10–11 years is ig- The main objective of this study was to find nored, it gives a new linear regression equation out the amount of compost landfill mining that (Figure 2). It will be corrected on the excavated can be obtained based on the age of garbage point at 10–11 years (x = 4) to 51.82%. Then, on heaps. This finding can be used as a wise con- the excavation point ≥ at 12 years (x = 5) it will be sideration to recover a landfill at the right time. corrected slightly from 55.91% to 57.62%. Table 1 shows the percentage of compost landfill This correction shows that the percentage of mining and other rough materials. compost landfill mining at the 10–11 year excava- Table 1 shows that the percentage of compost tion point is slightly increased than the 8–9 year landfill mining increases along with the age of excavation point in Table 1, i.e. 1.51%. The in- garbage heaps, respectively achieves 33.56% for crease is very small and does not have a significant 4–5 years, 38.46% for 6–7 years, 50.31% for 8–9 impact. Therefore, the excavation data at excava- years, 63.82% for 10–11 years and 55.91% for ≥ tion points of 10–11 years and ≥ 12 years can be 12 years. In the age group of 10–11 years, there is ignored, and landfill mining activities can be car- a fairly high increase in compost landfill mining. ried out at the age of garbage heaps of 8–9 years. In the same age group, the component of stone was Table 1 also shows that the 8–9 year of gar- obtained at 21.54%. It is greater than of the other bage heap produced compost landfill mining ex- four groups, which vary from 5–11%. The obser- ceeding 50%. The increase of the age of the gar- vation shows that the soil cover in the excavated bage heap in the next few years does not give a point contains more rocks. Covering the garbage significant increase in the percentage of compost properly requires more soil and the soil was mixed landfill mining. It shows that under the optimum as fine material. That is what causes the deviation conditions, the composting process can only of the amount of compost landfill mining obtained reduce the volume of solid waste by 50–70% in the excavated point of 10–11 years. (Hadisumarno, 1992). The impact of the deviation gives a linear line In Tamangapa Makasar landfill Indonesia, equation (Figure 1): landfill mining was carried out at 6 year cells. The y = 7.006 x + 27.394 (1) separation of fine material from plastic, paper, If the linear line equation (1) is interpolated wood, stone, glass, metal, and others was done by to the excavation point at 10–11 years (x = 4), the using a mechanical trommel machine, producing estimated amount of compost landfill mining will 50–60% fine material measuring < 50 mm (Dar- be corrected in a large decrease from 63.82% to wati, 2009). The percentage of fine material is 55.42%. At the excavation point ≥ 12 years (x = 5) slightly higher than this study because a lot of the

Table 1. The percentage of excavated garbage based on their age groups

4–5 years 6–7 years 8–9 years 10–11 years ≥ 12 years No. Components % % % % % 1 Compost landfill mining 33.56 38.46 50.31 63.82 55.91 2 Plastic 23.78 20.40 14.35 5.16 14.22 3 Metal 1.64 2.77 0.65 0.34 2.33 4 Paper 0.36 0.51 0.46 0.25 0.40 5 Wood 6.17 4.44 2.83 2.04 4.19 6 Stone 5.65 7.36 10.10 21.54 11.77 7 Coconut fibre 9.86 7.23 7.91 2.31 5.69 8 Nappies 14.01 9.99 8.03 1.73 2.37 9 Gla ss 2.36 4.32 2.74 1.89 1.77 10 Cloth 1.83 2.50 1.12 0.43 0.97 11 Rubber 0.78 2.02 1.50 0.49 0.38 Total 100.00 100.00 100.00 100.00 100.00

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Figure 1. Percentage of compost landfill mining generated by age group

Figure 2. Percentage of compost landfill mining generated without the age group of 10-11 years fraction of rocks passed the sifting machine. In respectively. In group ≥ 12 years, the percentage this study, the separation of fine material, includ- of metal is similar to the first two groups, which ing small rocks, was obtained manually by hands was 2.33%. A similar phenomenon is also shown (Figure 3). in the glass, cloth, and rubber components, in A method for sifting the dry excavated mate- which the percentage of the components is also rial to separate fine and coarse material was also almost the same, except for glass components in employed in the REMO Belgian landfill. The 6–7 years which is slightly higher. The phenom- excavated samples were selected in 4 locations enon shows that the existence of metal, glass, that varied at 14, 19, 24 and 29 years. Figure 4 cloth, and rubber from year to year tends to be shows the percentage of fine material obtained fixed as they do not decompose like organic ma- (40–50%) (Quaghebeur et al., 2013). terials (Figure 5). Paper is an organic component, but its occur- Time effect on an increase in the rence in the landfill is also relatively fixed. The pa- percentage of compost landfill mining per waste such as those from office, books, news- papers, magazines, and cardboard boxes goes to Table 1 presents some non-organic com- industries due to its economic value. As ponents that show a small change of percent- paper waste was sorted in households, shops, and age, except plastic and stone. For example, the also by scavengers, only a small amount of paper percentage of metals in 4–5 years is 1.64% and component ends up in the landfill – this type of then it increases slightly to 2.77% in 6–7 years. paper waste is from beverage packaging wrap- In 8–9 years and 10v11 years the percentage of ping coated with plastic, inside and outside, mak- the metal component is small, 0.65% and 0.34% ing it difficult to degrade naturally.

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Figure 3. Manually sorted and size of fine material

Figure 4. The percentage of fine materials at 14, 19, 24 and 29 years in REMO Landfill Belgium

Figure 5. The percentage of non-organic components

The percentage changing of plastic compo- for that in the 10–11 years group which is 21.54% nents and nappies is very significant, and in a lon- (as discussed above). ger time, their percentage also decreases. Howev- The two last components are wood and coco- er, this does not indicate that plastic and nappies nut fibre, which are classified as organic compo- have degraded through time. The phenomenon is nents. They can degrade through time and con- related to a changing lifestyle of local people and tribute to the increase of compost landfill mining this will be discussed in the next session. percentage. In Table 1, the percentage of wood in Stone is a solid material, and its occurrence the 6-7 years group is 4.44%, assumed as a result in the excavated garbage varied between 5.65– of 1.73% further degradation from the 4–5 years 11.77%. It did not have a significant impact on group. Meanwhile, the percentage of coconut fi- the increase of compost landfill mining, except bre in the 6–7 years group is 7.23%, assumed as

95 Journal of Ecological Engineering Vol. 21(8), 2020 a result of 2.63% further decomposition from the An increase in solid waste in the metropolitan 4–5 years group. The sum of both extra decompo- community is also seen at the percentage of nap- sition percentages gives a value of 4.36%, and if pies component obtained, including female sani- added to the percentage of compost landfill min- tary pads. At the excavation point ≥ 12 years, that ing in the 4–5 years group, it will give a value of is around 2004–2005, the total percentage of nap- 37.92%. This value is nearly similar to the per- pies was only 2.37%, but at the excavated point 8-9 centage in the 6–7 years group, which is 38.46%. years and 4–5 years it increased sharply to 8.03% This shows that the organic materials will decay and 14.01%. It shows that the income of the Banda over time naturally. However, further evidence in Aceh people has been improving as they can afford the next age groups did not provide a comparable these items. Unfortunately, it causes an increasing value. It was assumed that the initial percentage amount of plastic as a non-degradable waste that of wood and coconut fibre components or other must also end in a landfill site. organic materials in other age groups are greater On the basis of the discussion above, it can than the 4–5 years group and the organic materi- be concluded that the increase in the amount of als have degraded naturally. solid waste is not solely caused by an increase in the human population. An increase in income, The current condition of Banda Aceh people changes in lifestyle, and changes in consumption based on the solid waste generated patterns also have a very serious impact on the solid waste generation. Therefore, even though Generally, the components of garbage heaps people’s perceptions and knowledge about waste in this study are not much different from other are increasingly positive, it does not necessarily landfills. However, there are interesting compo- change the paradigm, mindset, and behavior of nents to be discussed: plastic and nappies (includ- the community in minimizing solid waste signifi- ing female sanitary pads). The components can cantly. A landfill is still the final solution to solid indicate an aspect of the current condition of peo- waste (Fehr, 2006; Mahyudin, 2017; Akhtar and ple of the Banda Aceh city that has been similar Soetjipto, 2014). to a metropolitan community. In Table 1, it can be seen that the percentage of plastic waste components obtained at the excava- CONCLUSION tion point ≥ 12 years is 14.22%; this plastic waste was generated during the period of 2004–2005. The recovery of landfills dominated by- or However, the percentage of plastic components ganic solid waste with high water content, espe- continues to increase over time. At the excava- cially in developing countries, can be done by us- tion point 6–7 years (2011–2012) the percentage ing landfill mining methods at the age of garbage reached 20.40%. Furthermore, in the 4–5 year heaps around 8–9 years. In the age, the percentage (2013–2014) it reached 23.78%. The dominant of compost landfill mining will be obtained in at plastic component is plastic bags. Plastic bag do not least 50%. The remaining excavated garbage can have sufficient economic value or heat value to be be sorted, separated and recycled (≥25%), where- recycled, so it must end in a landfill site (Figure 6). as the components which have no economic value

Figure 6. Plastic waste from excavated garbage

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